We need a mechanism to build Fuel ISOs with different “flavors”. Currently,
it is only possible to specify MIRANTIS=yes flag to create an ISO with
Mirantis logo, but we need to configure ISO build in a more flexible way.

A key “feature_groups” needs to be added to “VERSION” section of settings.yaml.
It should contain a list of strings, which presence in this list should be
checked in a few places such as footer, settings tab, role list, wizard, etc.
These checks also can be written as restrictions in configs: